Authentication Bypass in ZITADEL 3.x and 4.x by ZITADEL
CVE-2026-109372

9.3CRITICAL

Key Information:

Vendor

Zitadel

Status
Zitadel
Vendor
CVE Published:
12 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-109372?

ZITADEL versions 3.4.15 and earlier in the 3.x series, along with all 4.x versions prior to 4.19.2, are susceptible to an authentication bypass due to a flaw in the SAML identity provider's intent callback mechanism. This vulnerability occurs when the assertion signature verification process incorrectly matches the user to an incoming request without ensuring that the specified provider aligns with the expectations. Malicious users with organization-administrator rights can leverage this exploit by registering a SAML provider, employing their own signing key, which allows them to create authenticated sessions as any user linked to a different SAML provider within the same instance. This issue raises significant security concerns, particularly with account takeover possibilities across different organizations utilizing ZITADEL.

Affected Version(s)

zitadel 3.0.0 < 4.19.2

zitadel 4.19.2

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

cortex9-zitadel-saml-idp-intent-mismatch-model
Created by federiconbaez

References

https://github.com/zitadel/zitadel/security/advisories/GH...
vendor-advisory
https://www.vulncheck.com/advisories/zitadel-3.0.0-before...
third-party-advisory

CVSS V4

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

livio-a
IAM-marco
everping
AdamKorcz
.